motor is failing so you can refurbish it
guide here http://www.350z-uk.c...ttachment-incl/
if still no good you will need to buy an new motor from one of the traders here
+1 But after you have applied some Blackfire Wet Diamond
funnily enough Dave I was going to mention that when I posted. It is great stuff. Not cheap compared to when I bought it a couple of years ago but it does last. Leaves a superb glassy finish before applying was. I have to say Blackfires wax is pretty impressive too.
I'm surprised you didnt do your research before handing over your phone. Thats would be the sensible thing to do.
I used orange last time to sell phone and was excellent. Phone wasn't even a orange phone